Other Interesting Ideas

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ThreeDee wrote: So here's my question: is this just too obscure a filter to submit? Or a sure-fire HU when you batch every PNG image on the web in search of more steganographically hidden images...? Big grin Okay, I think I know the answer: if I make a Steganographic Encoder as well, it will be worth it, right?

Oh, you should submit it, just for coolness factor!

You turned a tree into a cat ?! Awesomeness.

jffe

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Kraellin wrote: stegano what? i see some trees and i see a cat.

Steganography (scroll down to "Example from modern practice") -- hiding an image inside an image.

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Carl wrote: You've encoded the cat pic with the tree pic but to make a decoder to get it out again that is a challenge - hats off if you can acheive that

So far I've only made the decoder, the encoded image is from the wikipedia article.

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ThreeDee wrote: Hahaa -- steganographic decoding solved!

I'm looking forward to see your solution - I've been trying to make a decoder too, also using step curve approach.. however when I get to the difference step, I don't get anything but black as result ..GRRR..

It took 2 mins to hack the decoder together in Delphi, but that darn AND operation is what is causing problems in FF.

Basically what I did in Delphi was this:

BITS = 2;

M := 255 - (BITS + 1);
S := 255 div (BITS + 1);

R_out := Abs(R_in - (R_in and M)) * S;

and the same for G and B.. works perfectly.. not so easy to get into FF though..hehe

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Sphinx. wrote: I'm looking forward to see your solution - I've been trying to make a decoder too, also using step curve approach.. however when I get to the difference step, I don't get anything but black as result ..GRRR.. It took 2 mins to hack the decoder together in Delphi, but that darn AND operation is what is causing problems in FF. Basically what I did in Delphi was this: BITS = 2; M := 255 - (BITS + 1); S := 255 div (BITS + 1); R_out := Abs(R_in - (R_in and M)) * S; and the same for G and B.. works perfectly.. not so easy to get into FF though..hehe

Yup, notably easier with a couple of lines of code and in native 8-bit environment.

In fact, it was much easier with just plain Photoshop with a couple of layers and curves than with FF.

Since this is such a ridiculous filter and I don't know if I'm going to bother to try and figure out the encoding side of it, here's the 2-bit Decoder in case someone wants to try it out. At least it worked with the wikipedia sample. I couldn't even find other samples to try it on.



Steganography Decoder.ffxml

how do you make an if-then branch in FF?

Example:

IF (slider A > 20) THEN (picture of apple): ELSE (picture of banana)

Wherein Slider A would be converted to a gray tone (Assemble HSL) and thresholded by 20 to blend 100% or 0% between Foreground (apple) or Background (banana).

k, it is like the left and right strands then. got it. so, the source input is the IF. cool i'd never even thought of various operations in FF as boolean or code-like. got any more?

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A(Blend Lighten)B = A OR B

hmmm, not sure i get that one, but then i'm not sure i understand exactly what lighten does other than it seems to bleed the lighter parts of two objects through to the top. but not even sure of that.

you'll have to forgive my ignorance, TD. i work mostly on effect stuff where i dont particularly have to know the math, logic, boolean and so on. i just have to be able to see but i am somewhat familiar with boolean from early computer studies. i'm just not quite seeing how lighten is an OR. i would have thought it would have been more of an inverse of darken and therefore just another AND but based on a different base.

and A(Invert) = NOT A, i think i understand. you're saying there that any value (A), inverted equals NOT A... i think

interesting. always fascinates me what people use to think with. i'm more a visual and audio computer, where folks like yourself seem to be more mathematically oriented. and jffe, well, jffe is a special case and we're still trying to figure him out

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Kraellin wrote: you with me on this, dilla? and let's share that popcorn, eh?

I'm with you on that one (i.e. the lightning filter), although the thresholds are no news to me...

OMG! ThreeDee thats so clever!
I was looking at your Suburbia filter thinking "how the hell did he do that?" came then saw your disco ball read the info - didnt undersatand it lol - followed your link to the forums and DL that png image to test it... and I am amazed!
Hate clever ppl

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Blending two inputs (A and B) equal the following operations: A(Blend Darken)B = A AND B A(Blend Lighten)B = A OR B A(Blend Difference)B = A XOR B as well as A(Invert) = NOT A

i've been studying this lately and i was wondering if you had a method of subtraction using blends and thresholds...or any other components, for that matter. i looked at a blend with 50% opacity in normal, but that's not really a subtraction. it's more of an average. but i could sure use a subtraction if you've got one. in other words, i need an A - B.

Yup, looks like that does it.

A - B.ffxml

Oh, I see. No, the above is subtracting one value or grayscale image from another. So you are looking at just taking an area which is A AND NOT B, where A and B are threshold results, right?

That would be then as simple as Inversing B and blending A and B with Minimum.

Or, even simpler, making Inverse B the High Input of Threshold A.

If I understood what you are trying to do correctly.

I'll post a snippet here shortly.

ok, am looking at your new one here and it looks like masking, and if i substitute in an 'image' component for the perlin and the other source, then it simply looks like an 'and'. so, let me try this again.

what i'm trying to do is subtract the results of one threshold from another in order to isolate a value or range of values within those threshold values. hmm, that's not saying it very well either. take a look at the filter i'm posting here. it's a very slight variation of yours where i've simply substituted in 'image' components. i want to threshold each of those image components with different threshold values then subtract one from the other. but, i dont want to add the results of each threshold leg; i want to subtract one from the other... A - B.

the basic idea, what this is all leading to, is that threshold is limited as it is in extracting values. it's a very linear thing. the threshold simply moves down the line and keeps limiting values (or adding, depending on which way you're moving the slider). but, this doesnt give you all that's possible or shld be possible for extractions. for instance, it shld be possible to extract just one color or one grayscale or a range of colors or a range of grays but using the thresholds to subtract one value from another. or, maybe it would work better with tone curves. but, let's stick to thresholds first. think of it as like doing a shadows/midtones/highlights type of filter. you want to extract a range of values to be the shadows and a range for the midtones and a range for the highlights. but, there is no extraction component like that. would be nice if there was, but there isnt. it would also be nice if there was a subtraction blend mode, but there isnt, at least not that i know of.

at any rate, there's a number of useful filters that can be done by being able to isolate a value or range of values and i think the secret to doing them is having a threshold subtraction method.

A-B rthresholdt by ThreeDee rev 1.ffxml

Height Painting

This idea came from Corvus Croax's spacecraft development. Painting onto a height map from the side (as opposed from the top).

Rather than the theory, here's a simple example of it.



And here's the filter.

HeightPainting.ffxml

well, TD, i thought i could pit one threshold against another inverted one and get a subtraction by adding the two together in a blend, but it doesnt work. so, i'm still stuck without being able to isolate a single color (with no blacks or whites either). i'm open to any other suggestions.

hi TD,

all i'm after is to be able to isolate a single rgb value to begin with, and after that, a range of values, like all the reds, or all the oranges/reds of the life preserver, for instance. it would be similar to the magic wand in photoshop/paint shop pro in that you could pick how wide or narrow a range you wanted to capture.

i see it more as a snippet that i, and others, could use to isolate those ranges and then treat just those ranges within a filter.

it would also be nice if it could distinguish lights and darks, as well... (again, like the magic wand) i suppose you could get into many different ways to isolate values and that would be great, but for the first, i'd just like to be to isolate and display a single value or small range of values.

there are color isolate filters already. i did one based on someone else's isolate, but they never quite achieved what i wanted.

such a filter, if it could really be made powerful and sensitive, could also act as an extractor tool, but that's down the road a bit.

the threshold component seemed like a good place to start, but it works on a linear basis with no subtractive element to it. it's just shifting down (or up) and doesnt isolate really. so, i thought if you could do two thresholds and invert one and then subtract one from the other, you could have what i was after. but, so far, i havent been able to make that work.

i also looked a mike's color picker, but that's doing something else. still, there might be something there of use to this.

anyways, whatever ya got, i'm interested

Okay, here's one simple but good way of doing it:



Range Selector.ffxml

Then you could make separate Range and Smoothness controls for Hue, Lightness and Saturation if you wanted to get fancier. 'IF' being the operative word.

Did you try my filter? It sounds so much like what you're trying to explain.